<template>
  <div class="swiper-container" ref="cur">
    <div class="swiper-wrapper">
      <div class="swiper-slide"
           v-for="(slide, index) in skuInfo.skuImageList"
           :key="index"
      >
        <img :src="slide.imgUrl"
             :class="{ active: currentIndex == index }"
             @click="handler(index)"
        />
      </div>
    </div>
    <div class="swiper-button-next" @click="add"></div>
    <div class="swiper-button-prev" @click="minus"></div>
  </div>
</template>

<script>

  import Swiper from 'swiper'
  import "swiper/css/swiper.min.css";
  import { mapGetters } from "vuex";
  export default {
    name: "ImageList",
    data() {
      return {
        //控制小图类名的索引值
        currentIndex: 0,
      };
    },
    computed: {
      ...mapGetters(["skuInfo"]),
    },
    watch: {
      skuInfo() {
        //保证数据发生修改,页面结构再次渲染完毕。在初始化Swiper实例
        this.$nextTick(() => {
          //初始化Swiper类的实例
          var mySwiper = new Swiper(this.$refs.cur, {
            //设置轮播图防线
            direction: "horizontal",
            // loop:true,
            // 如果需要前进后退按钮
            navigation: {
              nextEl: ".swiper-button-next",
              prevEl: ".swiper-button-prev",
            },
            //展示区域同时展示三张图片
            slidesPerView: 3,
            //每次切换的个数
          });
        });
      },
    },
    methods: {
      //小图的点击事件
      handler(index) {
        //修改响应式数据存储当前用户点击的索引值
        this.currentIndex = index;
        //全局事件总线，通知兄弟当前图片的索引值
        this.$bus.$emit("sendIndex", index);
      },
      minus() {
        this.currentIndex--;
        if (this.currentIndex <= 0) this.currentIndex = 0;
        this.$bus.$emit("sendIndex", this.currentIndex);
      },
      add() {
        this.currentIndex++;
        if (this.currentIndex >= this.skuInfo.skuImageList.length - 1) {
          this.currentIndex = this.skuInfo.skuImageList.length - 1;
        }
        this.$bus.$emit("sendIndex", this.currentIndex);
      },
    },
  }
</script>

<style lang="less" scoped>
  .swiper-container {
    height: 56px;
    width: 412px;
    box-sizing: border-box;
    padding: 0 12px;

    .swiper-slide {
      width: 56px;
      height: 56px;

      img {
        width: 100%;
        height: 100%;
        border: 1px solid #ccc;
        padding: 2px;
        width: 50px;
        height: 50px;
        display: block;

        &.active {
          border: 2px solid #f60;
          padding: 1px;
        }
      }
    }

    .swiper-button-next {
      left: auto;
      right: 0;
    }

    .swiper-button-prev {
      left: 0;
      right: auto;
    }

    .swiper-button-next,
    .swiper-button-prev {
      box-sizing: border-box;
      width: 12px;
      height: 56px;
      background: rgb(235, 235, 235);
      border: 1px solid rgb(204, 204, 204);
      top: 0;
      margin-top: 0;
      &::after {
        font-size: 12px;
      }
    }
  }
</style>
